Rotary drying apparatus



Aug. 30, 1932.

ROTARY -DRYING APPARATUS H L. CORWIN Filed Ilarch 12, 1930 4 Sheets-Sheet 1 INVENTOR.

Q lhrry L. GarWl/L m W/m ATTORNEYS Aug. 30, 1932. H. L. CORWIN v 1,373,995

ROITARY DRYING APPARATUS Filed ilarchlz, 1930 4 Sheets-Sheet 2 flurry L. Corm/z,

A TTORNEYJ INVENTOR. v

Ag. 30, 1932. H. L. coRwiN ROTARY DRYING AFPARA'LUS Filed latch 12. 1930 4 Stunts-Sheet 3 INVENTOR. flurry L. 600ml,

By M fi/ M/ ATTORNEYS Aug. 30, 1932. v H. coRwlN 1,873,995

ROTARY DRYING APPARATUS Filed March 12, 1930 4 s'neeis-sneet 4 INVENTOR. flax/ L. Carma,

A TTORNEYJ Patented Aug. 30, 1932 are) v STATES HARRY ,L'. conwnv, on warrior max, VGALIFQBN-IA ROTARY DRYING rr AR'AT s Application filed March 12 1930. seriai'uo. 435,168.

This invention relates to drying apparatus and particularly to drying apparatus of the rotary drum type in which material comprising solid material to be dried is' deliveredin" not necessarily slightly inclined to the horizontal, said'material being heated during its passage through the drum, as for example by passing a gaseous drying medium such as a body of hot combustion gases through said drum, so as to drive off moisture therefrom, I and the dried material being removed from 15 the other end of the drum.

An important object of this invention is to providea drying apparatus of this type so designed as to minimize or substantially prevent the leakage of air into the drum or of gas out of the drum at the point where the material is fed into and removed from said drum, as well as the escape of dust or finely divided material from the material-being dried. In drying apparatus of the type in which a hot gaseous drying medium is passed throughthe drum it is necessary to make connections at each'end between the rotating drum and suitable fixed structures so 'as to provide for inflow and outflow of such drying medium and it is also necessary to provide for continuous orinter mittent introduction of material to be dried to one end and for continuous or intermittent removal of the dried material from the other end. In the driers now in use, these connections and material 1nlet and'outlet means are such as to permit either outward leakage of the hot drying medium or inward leakage of the outside air,

either of which decreases the drying efficiency 40 of the apparatus. Any mechanicalmeans of sealing the leakage at this point, tight enough to be eiiective causes a great deal of friction between the stationary and rotating parts, as well as requiring constant adjust-mentto compensatefor wear; The forms of 'appa ratus now in use also permit dusting, that is, the escape of more or less of the more finely divided portions of the solid material being fed to or delivered from the dryingapparatus. This dusting not only represents a loss of material, but is also frequentlyob-- jectionable as constituting anuisance due to the introduction of this material into the surrounding atmosphere.

According to my invention the above disadvantages. are overcome by providing the rotating .dum with an end wall closing ofi thev major portion of the cross sectional area of the drum at'eac'h'end 'thereof; said drum being preferably further provided with a central passage means of relatively small cross-section as compared to the drum, extending through the end wall at the lower or material outlet end of the drum and secured to rotate with said drum, suitable means for maintaining a positiveinflow of hot gaseous drying medium through said passage means, another. central passage means, also of relatively small cross section, opening through the end wall at the upper or materialinlet end of the drum and secured to rotate with said :drum, and suitable means for maintain ing'a positive outflow of spent drying inc-- dium through said last named passage 'means; and by also providing means for feedinglthe material to be dried into said drum, and for delivering the'dried material from the other end of the, drum,'independently and separately from said inlet and outlet passage means for' the drying medium, and in such; mannerthat the solid material itself is caused to form a seal to substantially prevent inflow or outflow of air or 'gas through said material feeding or delivering means. Themeans which I use for feeding and deliveringthe-solid material comprises essentially continuous passage means extending aroundthe axis of the drum throughout at least'substantially one complete revolution,,said passagemeans opening exteriorly of the drum at one end and opening into the interior of the drum at the other end, so that material "may be caused to pass through said passage means upon rotation of the drum while maintaining'at all times a body of material in said passage means at the lower part ofthe drum of suflicient size to serve as a seal against passage of gas or air.. At the ma terial inlet end of the drier thepassage means areso' arranged that rotationof the drum in the direction of normal operation will cause the solid material to pass in a direction from the exterior opening to the opening into the interior of the drum, and suitable means are provided for supplying material to position to enter said exterior opening. At the material discharge end of the drier the passages are arranged in reverse manner, that is, so as to provide for passage of the material, upon normal rotation of the drum, in a direction from the interior opening to the eX- terior opening, and suitable means are pro: vided for discharge of material from said exterior opening.

In order toprovide for more nearly continuous delivery of thesolid material into and out of the interior of the drum I prefer to provide a plurality of such passage means.

at each end of the drum, each of said passage means being provided with openings at each end and the openings of the respective passage means being spaced angularly of the drum. Sa1d passage means at eachend are arranged for passage of the material there through in parallel. As the exterior opening of each material inlet passage moves through the lower portion of its path of revolution a certain charge of solid material enters through said opening and such material passes continuously through said passage means upon continued rotation of the drum and is delivered to the interior of the drum through the interior opening of said passage when said opening is in position to permit delivery of such material therethrough by gravity. Similarly, as the interior opening of each passage at the material outlet end of the drum passes through the lower portion of its path of revolution, a portion of the material from the interior of the drum enters said passage and passes around therein and is discharged from the exterior opening when said opening is in position to permit such discharge hy gravity. The portions, of material thus contained in the respective passage means are suificient to substantially obstruct th-e'passage at all times-against passage of gas or air therethrough.

A further object of the invention is to provide improved means for feeding the material .to be dried into the drying drum and particularly to provide feeding means adapted to elevate such material from a position drying medium and deposited in said stack.

A further object of the invention is to provide means within: the drum for controlling the rate of feed of solid material therethrough so as to provide for the proper contact of such solid material with the drying medium. A particular object in this connection is toprovide means whereby the rate of movement of the solid material longitudinally of the drum is controlled in accordance with the size of the individual particles or fragments thereof, so that particles of relatively larger size are caused to movemore slowly throughthe length of the drum and.

are thus subjected to the drying action for a longer period of time than the particles of relatively smaller size, thus tending toipromote uniform drying of the material regard less of the size thereof.

A further object of the invention is to provide improved means for eflecting discharge of the dried, solid material from the interiorof the drum, and a particular object in this connection is to provide for discharge of all of the material through a central discharge opening of smaller diameter than the shell of the drum. Due to the smaller diameterof this discharge opening, the lower. portion of said opening is at a higher levelthanthe lower portion of the periphery of the drum, and the material is, therefore, discharged at a higher level than would be the case ifit were merely permitted todischarge from the drum at the lower portion of the periphery thereof. This raising ofthe level of discharge of the dried material may beof advantage in certain'cases. As for instance malring it unnecessary to either elevate the dryer or dig a pit for an elevator boot'when the dryer discharges into an elevator.

The accompanying drawings illustrate embodiments of my invention and, referring thereto:

Fig. 1. is a longitudinal Vertical section, partially in elevation, of a preferredform of drying apparatus according to my invention. I

' Fig.- 21s a transverse section on line 2--2 in Fig.1.

Fig. 3 is a transverse section on line 3 8 in Fig. 1. V

Fig. 4 is a transverse section on line 4l in Fig. 1. V

Fig. 5 is a partial sectional view on line 5-5 in Fig- 1.

Fig. 6 is a planview of an apparatus siin ilar to that shown in'Fig. 1, but with a masses modified arrangement vot the means for de littering the solid material to the .ifeed end of the-drum and; for connecting the drying mediuinoutlet toithe stack. I

Fig. Tis a vertical sectionon line 7-o.7 in Fig.6. F-ig. S is a longitudinalyerticalsection of another modification of theinvention.

Fig. 9 is a plan view of the ;,upper ormaterial inlet 'endof the apparatus shown-in Fig.8, partly broken away.

7 Fig. 10 is a transverse section -oI-1 -;l-ine 10"1 0 in Fig, 8. v

V Figgll isa plan view of the lower or material outlet end of ,the apparatus shown in Fig.8., partly" broken away.

Fig. 12 is a transverse section online 12-12 inF-ig8. l

Fig. 13 is a partial longitudinal-section showing amodified arrangement of the material outlet passages. f

, Fig. 14 is a transverse section-on line 141 i in Fig.13. v V I Fig. 15 is a partiahel-evation taken in the direction indicated -the,line 15-15 in Fig. 14. i a i Fig. 16 is a transverse section on line 1616 in Fig. 13. I H

The form of apparatus-shown in Figs. 1 to 5 inclusive comprises a rot-atably-mounted drum including a cylindrical shell 1 of any suitable length and-diameter, and end plates or walls 2 and 3 secured respectively to the upper and lower ends .of said :shell in any suitable manner andserving to close the respective ends thereof throughout the major portion ofthecross sectional area ofthe drum. Said drum may be rotatably supported and driven in any suitable manner and is shown as provided with two track rings 4 supported on rollersi5 mounted :on supports -6.- Rota tion of the drum be .eli'ect'ed :bydrivirig some .or all of the rollers 55, .or otherwise, in the usual manner of such rotary drying apparatus, for example a motor 7 may be provided, d riving bevel gear 7a meshing wit-h bevelgear 7 I) attached to one of the rollerst5 as shown in Fig. 4:. The drum isshown as mounted for rotation about an axis which is inclined slightly downward from the material inlet end tojrthe material outlet end thereof, although such inclined :mounting is not essential to myinvention.

,At the upper or material inlet .end of "the drum the end plate 2, or, if desired; a separate plate -orwall, extends out beyond the circumference of the shell 1 asindicatedat 2. and an annular flange 8 projects from ,the outeredgeiof the portion 2, said flange being preferably provided with an inwardlyinclined rim or lip 9 so that the space within said flange and lip serves asa hopper adapted to receive and maintain a body of solid materialsto be fed into the drum. @A tubular drum throughout ,at least substantially one opening 11 in the sidewall of a stack 12. Said .tubefits ro'tfatably within said opening. and should fit fairly tightly therein.

. The {solid materialto be'dried may be fed into the receiving hopper of the drum in any suitable manner, for example by means of an inclined chute 13 leading from a storage bin or hopper 14, said chute extending, for example, at one side of the stack12, as shown in Fig. 5 and having its-discharge opening 15 projecting over the lip 9 in position to deliver material intojthe-space within said lip. In order "to provide for return to :the drying 'drum of' any finelydivided solid material carried over into the stack and subsequently settling therein, th-eolower portion of said stack below the opening 11 may be provided with a collecting pocket having an inclined bottom 16 and a chute'17 may be provided leading fromthe bottom of-said pocket to a position over the lip 9.. Said chute maybe normally closed by a gate 18 having handle means 19 whereby said gate may be. opened T he material inlet passage means are shown as provided by means ofa plate 20 extending outwardly from the shell, parallel to and spaced from the plate portion 2', and a plurality o-f'concentric partition plates 21, 22, 23 and 24 extending between plate 2/ and plate 2Q. In theexample shown, there are three in leto-penings 250,125?) and 250, equally spaced around the drum and establishing communlcation between the hopper space inside the flange 9 and the space between the'two outer partition plates .23 ,and24, but it will be underst'oodthat any :suitablenumber of such openingsm'ay be provided. Each of the intermediate partition plates 21-, 22 and23 is provided with three openings 26, and inclined deflectors or partition plates '2? connect the adjacent concentric partitions at opposite sides of said openings. The shell 1 is also provided with three openings 28a, 28b and 280 establishing communication between the space between said shell and the inner partition plate 21, and the interior of saidshel'l. The above construction, therefore, serves to definezthree separate passage means indicated at 29a, 29b and 290 for conducting material to be dried from the respective openings 25a,

25b andl 250 tothe' corresponding openings 28a, 28b and 280, during rotation of thedrum. Each of'said passages extends around the member 10 is secured centrally of the end complete revolution, and preferably throughout somewhatmore than 360, and extends progressively inwardly of the drum from the position of the exterior openings a, etc., to the'position of the interior openings-28a,etc. I prefer to-provide deflector plates 30 secured to the end plate and projecting into' the interior of the drum between the respective interior openings 28a, etc. and the center of the drum, as shown in Figs'l and 2.] a l -At the lower or material outlet end of the revolving drum, a cylindrical fire box31'extends through the end plate 3 and is secured to rotate with the'drum, for example by being securedto said end plate in any suitablemanner. Said fire box opens at its inner end as at 32into the interior ofthe drum and serves as a passage means for admission of drying medium to the interior of said'drum. Said passage means,- as shown, is-prefera'bly of materially smaller cross section than'the cylindrical shell 1; for example, the diam eter thereof may be from about to A the 'diameterof said shell. Said the box may be lined with suitable refractory material 33, and a burner 34 for liquid, gaseous'or solid fuel projects through the open outer end 35 of said lire box, whose interior also serves as a combustion chamber for the fuel admitted to said burner; It will be understood that other means for maintaining an inflow of hot gaseous drying medium through the central passage 31 may be used instead of that shown in the drawings, or that anyother suitable means may be employed for heating the material passingthrough said drum. The material outlet passage means ar shown as provided by means of a 'plate37 outside the end plate 3 and spaced from and parallel to said end plate, an annular plate 38 and a' plurality of concentric partition plates 39, 40, 41 and 42 within said annular plate, and suitably spaced from one another, all of said partition plates extending across between the end plate 3 and plate 37. I have also shown three material outlet openings 44a, 44b and 44c, equally spaced around the drum and establishing communication between the interior of the drum adjacent the periphery thereof and the space between the plates 3 and 37 and between the plates 38 and 39, it being understood, however, that any suitable number of such openings may be provided. Each of'the intermediate partition plates 39, 40 and 41 is provided with three openings 45, and inclined deflectors or partition plates 46 connect together the adjacent concentric partitions at the opposite sides of said openings. The innerpartition'plate 42 is also provided with three discharge openings 47a, 47?) and 47 0, equally spaced around said partition and establishing communication between the space between said partition plate and the adjacent partition plate and the annular discharge space .48 between said inner partition plate'and the lire box 31,

said discharge space opening exteriorly of the drum. The above construction, therefore,

serves to define thr'eese'parate passage means one complete revolution, and preferably throughout somewhat morethan 360, and extends progressively from the position of the interior openings 44a, etc.'to the position of j the exterior openings 47a, etc. I

'Discharge of the material from the space 48 may be facilitated by means of the outwardly inclined or flared annular apron 51 projecting from the edge of the inner parti- I tion plate 42,-and a suitable discharge hopper or bin 52 may be provided for receiving the material dischargedfover said apron and delivering the same to, any suitable conveying or storage means or the 1am;- Additional support for the fire box 31 maybe provided by the radial arms 53 secured to said fire box and to the outer edge portion of apron 51. In order, to insure the maintenance of a bed of solid material of sufficient depthadjacent the openings,44a, etc.,.the shell 1 is preferably provided withan outwardly inclined or'flared portion 54 immediately above the end plate 3, the plates3 and 37 being of somewhat greater diameter than the main portion of the shell '1, and the openings 44m, etc., being located adjacent the periphery of this flared portion, so that when said openings are at the'lower part of their path of revolution they will be at thebottom ofthe pocket-like space 55 thus provided, for maintaining a bed of solid material of increased thickness in position adjacent said openings.

It is entirely within the scop e' of the present invention to employ a shell whose interior is substantially smooth and unobstructed throughout its length, but I prefer to provide means within said shell for controlling'the rate of longitudinal movement of the "solid material therethrough. Such means may comprise, for example, aplurality of annular baffle members 57 extending around the drum at any suitable positions longitudinally thereof and inclined inwardly toward the masuitable manner as, forexample, by means of supporting frames indicated at 59. Said screens are of such mesh thatthefiner por tions of" the material to be dried" Willpass therethroughwith relativeease, while the larger particles or fragments of such" mate rial will passtherethroughwith difliculty or will be prevented fromdpassin'g through. the regular meshes thereofq Incase'the' solid ma-" terial being dried is ofsuchjnature that the larger fragments thereof will not be broken up by the agitatiomattrition or abrasion to which they are subjected: during "passage through the drum, to suffici'ently smal'lis'izerto ca l pass through the meshesof'said' sf c1-"een 'n'e'mrbers, said screen members maybe provided witha suitable number of relatively large openings 61 to permit passage therethrougli of such larger fragments" upon enooi'mte'rfing such relatively large openings,' butit will be understood thatfor useon materialsjof s'uch friable nature asto "be broken up hythe a'g'ifa tion to which they are subjected in passing through the drum, and particularly when the moistureis removed therefrom, bythe'drying medium, such larger openings 61" maybeomitted, as explained hereinafter, It will-be noted that the bafiie members 57- arid' the a screen member's'58 preferably doInot extend entirely across the interior of. the drum, so as to leave-a relatively free space through the center of the drum for the passage of thehotj drying mediumltherethroughg I i The drum may also advantageously, though.

5 not necessarily, v be provided with lifting vanes 63Iextending longitudinally o fthe drum and spaced at any suitableangul'ar positions therein, said lifting vanes being preferably inclined inwardlyand insthe direction of rotation of the drum, so as to cause the solid material to be lifted/to greater height at the rising side of the drum thanswould otherwise be the case, and thus increase the agitation of hot drying medium; 0; t; s, r

The operation of 'the above described" apparatus is as follows:.The material, to be dried comprising, in general, solid material in a suitable state of division, together with more orless water or other liquid material,-

is delivered through feedv chute 13 into the hopper space provided within the flange- 8.

and lip 9 at the lower portion. of the drum. Such material may, in some cases, contain free water or other liquid, so as to constitute a wet fluent mass, or thewaten or other liquid may be completely absorbed or otherwise: held by the solid material, soas to -form" a mass of more or less wet fragments or par ticles. Simultaneously with the delivery ofsuch material, fuel is delivered through burner means 34 and burned withinthecombustion space inside'thefire box, 31,}11'1. the presence of drawn inl through fthefopen ing 35. The hot combustion gasesthu's'pr'oduced' pass through the open-inner end 3201f the fire box through the length of the: rotating drum and thence through the passage means 10 and upwardly through stack 12; The draft thus produced ser'ves'to maintain aposi; tive inflow of hoti gaseous drying medium through the passage means within the fire box at the material outlet end of the drum and'a positive outflow of spent dryingme dium' through the passage means IO-ajt the material inlet end of the drum. The 'iht'e'nsity of such draft and consequently the rate of'floy'v of drying medium through the drum may be controlled byregul'ating the supply of 'fiielin any suitable manner and 'a-l'so' by' suitable draft regulating means such as damper-65' in stack 12. f

The materialfed onv to the lower portion eral material inlet openings 2564,2529} and225e as 'such openings successively reach the'lo'wer portion of the drum, and it may be'se'enby reference to Fi'g; 2 that the continuous totaltion of the drum will cause such materialfto' pass. inwardly through the correspondi'ng. passage" means 2%,296 and" 290 until; it reaches the openings 28a, 28b and 2822', through which such material is deliveredintothe interiorflof the drum d'uring'the upward I tive passage-means is always-in position" at thje'f wer portions of the several passages n sufficient amount to substantially completely obstruct the passages as indicated at, in; Figp2 and thus prevent; inflow of a'ir'or out? flow of: gaseous'drying medium through, such passages, In this form of the invention the several passages 1295;, etc; extend progres l sively [inwardly radially 'oflthe' drum 5 and hence serve-to elevate'the material from the levelat whichl it is delivered upon the flange T 8 andlip 9-v to the level of the lewen'porti'on.

of the 'inter'ior'lof the drum. When the levelofthe supply 'bin or hopper 14 is fixed, this arrangement of the passages is ofiadvant'age,

as it permits the material to be delivered bygravity into the material receivin space aboves'ai'd flange 'andlip and to be thus elevated suflicientl'y tdr'each' theinterior of the drum, thereb eliminating the necessity of providing other elevating means for this purpose. Y 5

It will be evident that the delivery of ma*-- terial through each ofthe openings communicating withv the intei iorof the drum will,

in general, be substantially completed by the time such opening reaches the ipo sition oflthe opening 280, in Fig.2,but the deflector plates, 30'ma'y nevertheless be of advantage in preventing any of such: material from being delivered into too close proximity to the outlet I passage 10 and thus being picked up and plane of the drum, and such an arrangement is shown in Figs. 6 and 7,. The material supply bin or hopper 14 is in this case provided" 7 within the flange 8 and lip 9 centrally of the lower portion thereof. The stack 12 may in this case be located somewhat to one s'ide of the drum and may be connected tothe tubular gas'outlet 10 by means of an lIlCllI 16Cl'LfiL1B'66 Whose lower end is provided with an elbow 67 for connection to said tubular outlett Said lower end of flue 66 may be mounted on suitable-supporting means such as 68. The returnfof dust carried over. into the inclined flue 66 may be provided for'in this case by.- means. of a dust return pipe or conduit 69 leading from. the lower end of said flue'adjacent elbow 67 to thefeed chute 13" and having a gate adapted to be normally closed to. prevent inward leakage of air through said pipe but to beopened when desired, to permit the dust collectedv above said gate to return to. the feed chute'13. The operation of this form of the invention is substantially the same as above described and is believedto require no further description.

Various modifications may also be made in the arrangement of the passages for effecting movement of the material to be dried into the interior of the drum and movement of the dried material out of the drum while preventingleakage of gas or air out of or into the drum. For example, as shown'in Figs. 8 to 12inclusive,'sa'id passages may have their convolutions or turnssuccessively displaced linearly of the drum instead of radially thereof. In this case the materialinlet passage means are shown as'provided-by-m-eans of acylindrical wall 72 surrounding and spaced from a portion of the shell 1 adjacent the material inlet end thereof, and a series of} annular partition plates 7 3 extending transverselyof the space between plate 72-and'shell lean'd serving to divide suchspace int'oa suitable number'of annular passages.- Thefirst.

partition plate 73 is shown as providedw'ith three inlet openings 25a, 25b and-250, and

each of the intermediate partition plates is provided wit-h three openings 26. Inclined deflectors or partition plates 37 connect the adjacent partitions 73-at opposite sides of said openings.

between the interior of the drum and the space between the last two partitions 7 3. The

in the form ofthe invention first described,

the above construction servestodefine three The shell 1 isalso provided with three openings, two of which are shownat 28a and 28b, establishing communication separate" passagemea-ns indicated: at 29a,

29b", 231(13'296, respectively, for conducting the material to be dried from the respective openings 25a", etc. tothe corresponding openings 28a, etc. during rotation. of the drum;

Each. of said passages, as before, extends around; the drum. throughout approximately 360 or more, but, extends in: this pase. progressiveliy' linearly of the drum from: the position. ofv the exterior. openings, 25a, etc; to

the positioniof'the; interior openings 28a etc. The end plate 21 of. the drum isshown asv provided'fas before with a centrally located tubular gas outlet passagerlO which may: be connected to a stack in any suitable manner, for example as shown i11.Fi'g;.1 or-in: Figs. 6 and 7 .L The flange- ,8" inthis. case extends from, the EQuter'redge of the first partition plate 743? andis shown as comprising a continuation. of the cylindrical wall 72; Said manner.-..

The material outlet passage means are shown. as provided :by means of a. cylindrical- Wallf75j surrounding and spaced-from a portion of the shell 1 adjacent the material outlet end thereof, anda'" plurality of -annular partition plates 7 6 extending transversely of the space between said wall and shell. The first of the partition plates 76 is shown as comprising an outward continuation of the end plate 3. The shell 1 is shown as provided with three material outlet openings, two of which are indicated at Ma and44b equally spaced around the drumand establishing communication between the interior of the drumand the passage between the first twopartitions 76; The last partition plate 767 is provided with three discharge openiiigs 47a.4'Z 'Ib,and 4% also equallyspaced around the drum and establishing commun1- cation between the space'between the partition plate 76 and the next partition 76 and the exterior of the drum. Each of the intermediate partition plates 76 isprovided with three openings 77, and'inclined deflectors or partition. plates-7 8 connect together the adjacent partition plates 76 at opposite sides of said openings, said deflectors being'inclined in suchdirection as to progressively displace the-material through the openings 77 in adirection from the openings 44M, etc. toward the openings 47a=',getc.' There are thus provided three separate passage means indicated discharge of the material deliver-ed outwardly through the opening 17a, etc; r

. The baflle members, screens and lifting vanes of Figs. 1 and 4 are not shown in Fig. 8, which illustrates the use of a plain cylindrical shell whose interior is free from any such obstructions or projections for controlling the lifting and the longitudinal movement of the material withinthe dI'LlITL- It will be understood that a shell of this'type may also be used in connection with the material inlet and material outlet means'shown in the first described form of the invention, and also that the baffle members, screens and lifting vanes shown in Figs. 1 and a may, if desired, be provided in the interior of the drum in connectionwith the material inlet and material outlet means shown in'Figs. 8

- let passage 10. There will, therefore, be little or no tendency for material delivered through said openings to be picked up by the gas and carried out of said passage and I have,therefore, shown in this, case no defle'ctormember corresponding to the deflectors of Figs. 1 and 2, although it will be understood that if H desired similar deflector means may alsobe provided in this case.

The operation of the material inlet and material outlet means of this last form of the invention has been already described in connection with the description of said means,

and the operation is otherwise similar to that of the form first described,'with the exception that when a smooth wall-ed cylindrical shell free from interior, obstruct-ions or projections is employed, as shown, the material will sim-' ply pass longitudinally through the rotating shell, while being continually lifted at the rising side of the shell due to friction of the shell wall, so as to be tumbled or caused to- 7 roll over and over, and fallthrough and in contact with the gaseous drying medium. The dried material delivered over the apron 51- may be received in any suitable storage means or on suitable conveying or handling means.

A further modification in the arrangement of the material delivering passage means is shown in Figs. 13 to 16 inclusive. This ar rangement is illustrated only in connection with the passage meansfor eflec'ting discharge of the dried material from the drum,

but it will be understood that it may also be applied inconnection with the passage means for effecting feeding of the material to be dried into the drum. 'The cylindrical rotatably mounted shell isshown at 1 and the end plate thereof at 3"; Said endplate is shown as provided witha portion 81 extendingoutwardly beyond the shell 1 and constituting an intermediate partition plate,

sides from said plate 81. A cylindricalwall 84 connects the outer edges of all of said partition :plates'.' An annular partition plate 85, concentric with the shell 1 and partit-ion plate 84-. and equally spaced th-erebetween, extends 'acrossbetween the plates 81 and 82, while similar partition plates 86, spaced at suitable intervals extend, across between the plates 81 and .83, the innermost of said iplates 86 being spaced somewhat outwardly from the cylindrical fire box 31, so as to provide a discharge space 18". The shell 1 is provided with three openings 44a,- 445. and 14:0", establishing communication from the interior of said shellinto, the space between said shell andthe partition 'plate 85, while said partition plate is provided with three openings 88. Adjacent said last mentioned openings are provided-inclined deflector'plates 89 adaptedto guide material through said openings from'the space inside partition plate 85 to .the space between said partition plate and the outer wall 84. Plate 81 is'provided with. three openings 91' establishingcommunication from said last are also provided adjacent said last men-' tioned openings for directingthe material therethrough. I I

It will be seen-that in this case three separate passage means are provided as indicated at 49a", 49b", and 490', said passages being defined by the shell 1, the plates 81 to 86 inclusive, and the several deflector plates 89, 92, 94, and 96. Said passages extend from the openings 440%, etc. and are displaced first outwardly, then longitudinally of the' drum, and finally inwardly and other partition plates 82 and 83 are also ima es,

thereof; to the openings*-47w"", ;eto.: ilnthez rotation of the drum the material will" pass:- through the openings 44w; et;,o., iaronnd' through said passages, and; out: throughthe -openings 470/1, etc; into the discharge space:

48'". Thexmaterial in :the lower portions of 1 saidpassageswill as before'formfan. eiiective' seal to prevent inflowof air or-ou-tflow of dryin zmedium therethrough. This form of" Q'fithe invention may also he provided with: an-

outwardly flared dischargeilip-olif' forffae V cilitating delivery: of mater-ial-ufrom thee space 48 into; any; suitable storageuor oen- Veying means or the like. Iclaim: V 1 v 1. A rotary drying apparatuscomprising 1 a rotatably mounted drum, .means ;atone end of said drum defining; passageimeans-sfor deliveringvmaterial, ito be; dried into the zoqdr um, said passage means extendinglaroundthe axis ofthe drum throughout.atvleastsubstantially 360 and openingexteriorlyot thedrum at one=end andsopeningjinto the interior of the drum at the other end and zfisbeing so disposed as to eftect movement ofmaterial from-theextenior opening, to the interior opening upon rotation-sot the drum in its normal'direction, mealnsmt theqoztherend of the drum defining passage means for sq delivery of dried, material from the-interior of-the drum to the exterior thereo-iy sa idlast named passage means-also extending, around the axisofthe drum throughout-at. least substantially 360 and opening into the v interior of the drum atone-enda-nd-opening eXteriorly ofjthe drum 7 at the: other; end and; i g so p d s efieeti: mo em nt' otr material from theinterior opening to the en,- terior openingthereof uponrotation of said A; 1 drum in its normal direction, means forfrm ta'ting said drum in said normal direetionf to cause material to be dried-to enter through said first named passage means a and to 93.5% longitudinally through said drum and gto be discharged through said last namedpassage eans and means for heatingtheimaterial passing through the (drum.

2. A rotary dryrng apparatus oomp rising a rotatabl-y mounted drum-,i means atone end v 50; of said drum: defining passagemeans =fQIfd9-j liveringmaterialito iloe dried into the drum, said passage .meansextendingaround the axis I of the drum throughout, at least substantially 360 and: opening exteriorly; of; the drl m at :oneend and opening into theintenionot the; drum vat the other endwand' being sodisposed as to eflect movementtoti matenialyfroinithe" exterior openingto the interior openingppon-- opening intoxtheiinterior; of: the drum at v one end and opening exteriorly? of .the drum at V therotherend and'being SOxdlSPOSGdf asto; ef feet; movementcof material 'from the-interior;

opening to: the exterior openingthereofi upon rotationofsaid drum in its norma-l;direction; and means lncludlng passage meansscom-u municating with the central portions otisa id drum for; efieotingspassageaof gaseousrdriyingr mediumtherethroughs p 3. In a: rotary drying-apparatus s; rotatahlyr mounteddrum, means-at one end ofrsaidl'drummounted so asto rotate withsjaiddr-uini and defining passage1mea-nsextendingaround the anis of thedrum throughout'at least fsulostantially- 360; said I passage Vmea'ns" opening ex teriorly ofthe drum at one end and opening" to the interior of the drum at the others end andloe ng so disposed as to: eiie'ct movement of" material from the exterior; opening to the interi'orr Opening upon 3 rotation of the-drum Tin its normal d-ireotlon, 'jmeans defining an 311'?- nulark materialreceiving space" ontsi'de-a'.thev- (1mm and "adj acent' the; exterior: opening: of

96 cause material to passtherefrom-through the said passage means, and s0 disposed? as: to

exterior opening nponrotation of said drumin said normal. direction, and -m'ea-ns fQr" rotatingsaid druminsaidnormal'direction:

- 4:. a rbtarydr'ying"apparatus-a rotatabl y mounted drum, means:definingz-.a cen tral ,outlet passage for spent drying medium: I

at one end of said drum, said passage hein-g of= materially smaller diameter than said drum,*n1eans at said end of the drum defining material inlet passage means extending aroundsaiddrum: throughout at least sub1-= stantially- 360 and outside the cross section oztsaadoutlet passage, said material vin-let passage meansopenin'g at one endlexteriorliyof the drum and opening vat'tlte other end intothe interior of the drum, means for delivering materialyinto said exterior opening, and means for-rotatlngfsaiddrum in such direc tlon as to causetsueh materlal to passloy gnavity'through said passagemeansto theinterior 1 p ing the e f-. r a y tra'l ou-tlet passage {for :spent; drying medium drzum ,-;nreans at gs aidendot the drum defin ma i' le pa age mea ex ending" I I H :120 stantially 3609 and outside the ;cross section of --sa -d "Pa a e, s id; mater a inl t around said Y-drum throughout at least sub? passage means opening at one end exteri'orly; the drum an nesi s -ithei the n into the interior of the "drumadjacent the al :o nto sa d: ex er p i g, m n o 'Qtat ngs i =dr1 Eimsuch .dire tenas to cause; such material-to pass by, gravity. through:

saidqpassa-ge meansandtthroughsaidinteri'or d yi g ppa t s 1 tatably mounted-drum, means defininga cenatv-one end of ,said drum sa-id passage;;loeing 1 materially smaller diameter than ,sa'id f .125 p riph ry h reef, meansicnd l v i s a" opening and deflector means positionedbe diuin'ioutlet' passage, so as to prevent mate-* =ria1;falling from said interior'opening from entering the outflowlng drylng medium imniediatelyadjacent said'outlet passage.

tatablymounted .drum,--means at one end of wgsaid drum defining a plurality of separate ma terial einlet passages, eachv extending around said drum throughout at'least substantially 360, eachof said passages having antopening at I one 1 end communicating with 5;; the exterior of thedrum and an opening at theother .:end communicating with v the interior of the drum and being progressively displacediin a direction from said exterior opening'towarld saidinterioropening, the

go exterior and interior openings of the respective' passages being substantially equally spaced around theaxis ofthe drum, means'for r deliveringmaterial into position to pass by gravity through said exterior openings when at the'lower part of the drum,-means for rotating said drum in such direction astoeffect movement rot such material throughffi's'aid passages froni sald exterior open ngs to sa ldinterior openings, and :means extending tiu through said end of'the drum iand se'parately fromsaid material inletpassages and defin ifigiain Outlet P s age for gaseous drying mel m from thejinterlor'of saiddrum 7'. In a rotary drying apparatus, a rotatably mounted drum, means at oneend' of said drum definingan' annular matem'ialjre ceiving" space outside the drum an'd comprising an annular lip adapted'to retain material'within said space-{the diaineteriof the inneredge of 40isaid lip being materially greater than the diameter of sai d drum w'vliereby'ma'terialj to be dried' niay be delivered into said space at a level below the lower-portion o'fthe-drum at'f's'aid end, means defining passage means 5 extending around said drum throughout at least s'ubstantially3609, 's'aid passage means having an exterior opening at one'end com-' munieating with said material" receiving space and an' in'te'r'io'r' opening at'the other 5- end c'on'imunicating'withthe interior of said" I I I I I I I I means extending around the axis of'sa-id drum throughoutfat -least substantially-36m and drum and; being progressively displaced in} wardly' toward the axis of said drum from.)

said 'exterio'r opening toward said interior opening; and" means for rotating said [drum in such direction 'a'slto' cause material to pass by-gravity aroundwithin said passage means from sa'id exte'rior 'opening to said interior 8. reaming;- drying apparatus,means 'defi'innga centrally disposed outlet passage em-e toretain materialwithin space, thedi drum, means for-efiecting movement of material from said material receiving space into the interior of-s'aiddrum upon rotation" of said drum,' ar stack communicating with fi6.".In. a"rotary dryingapparatus, a rodelivering material so collected to said ma- 5: municati'ng "outlet passage, and means -forterial receiving space gravity at a point i i below said outlet passage." I I 9. In a rotary drying apparatus,:a*rotatably mounted drum; means defining an inlet passage for'hot gaseousdrying medium extending through one end of said drumsub stantially centrally thereof and of materially smallerdiameter than said drum, means at said end of the drum defining materialoutlet passage means-extending around theax'is of said drum throughout. at least substantially 360and outside the crosssection ofsaid gaseous medium inlet passage, said inaspace outside the drum andpositionedto' permit'discharge of material from said passage means through said last named opening by gravity upon rotation of said drum, and means'iior'rotating said drum injsuch direc tion as to eausematerial to'pass'by gravity through said passage'means from said in-, terior opening to said exterior opening thereof. 10.'--In'a rotary drying apparatus,.a rotatably mounted drum, wall means closing the major portion 'ofone end of said'drum, means? defining an inlet passage for hot gaseous 4 drying medium extending through said wall meanssubstantially centrally of the drum and of materially smallerdiam- '00- terial outlet passage means having at one end an interior opening-communicating with the interior of'the drum and positioned to per mi-t passage 'ofunateriahfrom the drum eter than said-ldr'um, means atsaid end 'ofthedrum defining' material-outlet passage outside the cross section of said'gaseous me dium i'nlet passage, said'material outlet pas-- sage means "having 1 atone end an interior opening communicating with the interior of the drum adjacent tlie periphery thereof and in'gat its other end an exterior opening posiitionedto permit: discharge otmateria'ltherethrough bygravity uponqrotatio-n of 'said drum; means defining an annular discharge. space outside? said wall means in; position'to i no receive material discharges through said exterior opening, an annular discharge apron adjacent said discharge space and of materially smaller diameter than said drum, and means for rotating said drum in such direction as to cause material to pass by gravity through said passage means from said interior opening to said exterior open ing thereof.

11. In a rotary drying apparatus, a rotatably mounted drum, means at one end of said drum defining a plurality of separate material outlet passages, each extending around said drum throughout at least substantially 360, each of said passages havingan interior opening at one end communicating with the space inside the drum and an exterior opening at the other end communicating with the space outside the drum and being progressively displaced in a direction from said 111- terior opening toward said exterior opening, the interior and exterior openings of the respective passages being substantially equally spaced around the axis of the drum, and being so disposed as to permit passage of driedmaterial therethrough by gravity into and out of the corresponding passages upon rotation of said drum, means for rotating said drum in such direction as-to effect movement of dried material through said passages from said interior openings to said exterior openings, and means extending through said end of the drum and defining an inlet passage for gaseous drying medium to the interior of said drum and separately from said material outlet passages.

12. In a rotary drying apparatus, a rotatably mounted drum, means extending through one end of said drum and secured thereto and defining a combustion chamber communicating with the exterior and with the interior of said drum, burner means extending within said combustion chamber, means at said end of the drum defining an annular discharge space surrounding said combustion chamber and separate therefrom, an annular dischargeapron adjacent said discharge space, said discharge space and apron being of materially less diameter than said drum, means defining passage means extending around said drum throughout at least substantially 860, said passage means having an interior opening at one end communicating with the space inside the drum, and an exdrum, means for feeding material to be dried longitudinally through said drum, means for maintaining a flow of gaseous drying medium through said drum, and" annular bafiie members projecting inwardly from the wall of said drum and spacedlongitudinally thereof, said baffle members being inclined inwardly. in the direction opposite to the direction of liongiltudinal movement of the material to be 14. In a rotary drying apparatus, a rotat ably mounted drum, means for feeding material to be dried longitudinally through said drum, means for maintaining a flow of gaseous drying medium through said drum,means for rotating said drum, and an annular screen member extending inwardly from the peripheral wall of said drum and inclined inwardly in the direction opposite to the direction of longitudinal movement of the material to be dried, said screen member having a relatively large central openingfor passage of gaseous having a relatively large central opening for passage of gaseous'drying medium and also having an additional opening in its inclined surface of materially greater'size'than the regular meshes of said screen member.

In testimony whereof I have hereunto subscribed my name this 6th day of March 1930. HARRY L. CORWIN.

terior opening at the other end communieating with said discharge space and being progressively displaced inwardly toward the axis of said drum from said interior opening toward said exterior opening, and means for rotating said drum in such direction as to cause material to pass by gravity around within said passage means from said interior opening to said exterior opening.

13. In a rotary drying apparatus, a rotat ably mounted drum, means for rotatingsaid 

